I can't think of a situation that would cause this in an in-process addin. You can read about this topic in this MSDN article: http://msdn.microsoft.com/library/ms228772.aspx]How to: Fix 'Application is Busy' and 'Call was Rejected By Callee' Errors but the problem should only be for external out-of-process applications. We also covered this topic in the Solid Edge SDK. Search for keyword 'OleMessageFilter' in the SDK.
Without seeing what you're doing in your code, it's difficult to guess what the problem is. My advice in situations like this is to use 'process of elimination' to find the problem. What I mean by that is disable (remark) as much of your code as possible to get down to the bare minimum that you need for the addin to load and see if the problem still exists. If it does not, unremark pieces of code one at a time and continue the process until you've isolated the problem.
Posted by: Jason Newell Post date: 3/14/2012 5:52:25 PM